Distributed control modules with cumulating command references

ABSTRACT

A distributed control system may include a main processing unit, a distributed control module, and a controllable component. The distributed control module may be configured to receive a nominal command reference from the main processing unit, determine a series of cumulating command references based at least in part on the nominal command reference; and output a series of cumulating control commands to the controllable component. The series of cumulating control commands may be based at least in part on the series of cumulating command references.

FIELD

The present disclosure generally pertains to distributed controlsystems, and more particularly to distributed control systems thatinclude distributed control modules configured to provide cumulatingcommand references and corresponding cumulating control commands.

BACKGROUND

Distributed control systems generally provide increased reliability bylocalizing control commands to various distributed control modulesassociated with corresponding controllable components. A distributedcontrol system may include a main processing unit that sends nominalcommand references to various distributed control modules. In someimplementations, a distributed control module may have a faster clockthan that of a main processing unit. Differences in unit time intervalsbetween a main processing unit and a distributed control module mayintroduce noise into a control loop. Such noise may be introduced, forexample, when a distributed control module attempts to output controlcommands at a faster unit time interval than the unit time interval atwhich nominal command references are provided by the main processingunit. While the distributed control module could be slowed to reducenoise, this may reduce the responsiveness of a control loop implementedby the distributed control module to control the controllable component.

Accordingly, there exists a need for improved distributed controlsystems, including distributed control systems with distributed controlmodules that have improved capabilities to operate at unit timeintervals that are faster than that of a main processing unit.

BRIEF DESCRIPTION

Aspects and advantages will be set forth in part in the followingdescription, or may be obvious from the description, or may be learnedthrough practicing the presently disclosed subject matter.

In one aspect, the present disclosure embraces methods of controlling acontrollable component. An exemplary method may include receiving anominal command reference from a main processing unit, determining aseries of cumulating command references based at least in part on thenominal command reference, and outputting a series of cumulating controlcommands to a controllable component. The series of cumulating controlcommands may be based at least in part on the series of cumulatingcommand references.

In another aspect, the present disclosure embraces distributed controlsystems. An exemplary distributed control system may include a mainprocessing unit, a distributed control module, and a controllablecomponent. The distributed control module may be configured to receive anominal command reference from the main processing unit, determine aseries of cumulating command references based at least in part on thenominal command reference; and output a series of cumulating controlcommands to the controllable component. The series of cumulating controlcommands may be based at least in part on the series of cumulatingcommand references.

In yet another aspect, the present disclosure embraces computer readablemedium. Exemplary computer readable medium may includecomputer-executable instructions, which, when executed by one or moreprocessors of a distributed control module, cause the distributedcontrol module to: receive a nominal command reference from the mainprocessing unit; determine a series of cumulating command referencesbased at least in part on the nominal command reference; and output aseries of cumulating control commands to the controllable component. Theseries of cumulating control commands may be based at least in part onthe series of cumulating command references.

These and other features, aspects and advantages will become betterunderstood with reference to the following description and appendedclaims. The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrate exemplaryembodiments and, together with the description, serve to explain certainprinciples of the presently disclosed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure, including the best mode thereof,directed to one of ordinary skill in the art, is set forth in thespecification, which makes reference to the appended Figures, in which:

FIG. 1 shows a block diagram depicting an exemplary distributed controlsystem;

FIG. 2 shows a block diagram depicting an exemplary distributed controlmodule that may be included in a distributed control system;

FIG. 3 shows a block diagram depicting an exemplary controller of adistributed control module;

FIGS. 4A and 4B show block diagrams depicting exemplary aspects of acontrol command module of a distrusted control module, including aspectsof a command reference generation module;

FIGS. 5A-5C graphically show exemplary nominal command references inputto a command reference generation module and corresponding cumulatingcommand references output by the command reference generation module;

FIG. 6 shows a block diagram depicting exemplary aspects of a controlcommand module of a distrusted control module, including aspects of acontrol logic module;

FIGS. 7A-7E shows block diagrams depicting aspects of exemplary methodsof controlling a controllable component; and

FIG. 8 . shows a schematic, cross-sectional view of a turbofan enginethat includes a distributed control system with a distributed controlmodule configured according to the present disclosure.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present disclosure.

DETAILED DESCRIPTION

Reference now will be made in detail to exemplary embodiments of thepresently disclosed subject matter, one or more examples of which areillustrated in the drawings. Each example is provided by way ofexplanation and should not be interpreted as limiting the presentdisclosure. In fact, it will be apparent to those skilled in the artthat various modifications and variations can be made in the presentdisclosure without departing from the scope or spirit of the presentdisclosure. For instance, features illustrated or described as part ofone embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present disclosurecovers such modifications and variations as come within the scope of theappended claims and their equivalents.

The present disclosure generally provides distributed control systemsand distributed control modules that are configured to controlcontrollable components according to a series of control commands thatare based on a series of cumulating command references. A distributedcontrol module may provide a series of cumulating command references byupsampling a nominal command reference from a main processing unit. Inexemplary embodiments, the distributed control module (DCM) may have afaster DCM unit time interval (t) than that of the main processing unit(MPU), allowing the distributed control module to provide controlcommands at a faster unit time interval than the MPU unit time interval(u) associated with nominal command references from the main processingunit. The presently disclosed cumulating command references may reducenoise in a control loop, for example, by providing a series cumulatingcontrol commands that distribute a nominal command reference from themain processing unit across a DCM unit time interval (t). The cumulatingcontrol commands may be provided based on a series of cumulating commandreferences, which may be generated by a command reference generationmodule or other aspect of a distributed control module.

While a DCM may be configured to operate with a DCM unit time interval(t) that is faster than an MPU unit time interval (u), in general, thenominal command references from the main processing units may preferablybe distributed across the DCM unit time interval (t) rater than applyingthe nominal command references in a single step-change because such astep-change may introduce an undesired transient response. Suchtransient response may be attributable to the faster unit time intervalof the DCM versus the MPU, and the magnitude of the transient responsemay be proportionate to such difference in DCM and MPU unit timeintervals. The nominal command references from the MPU may bedistributed across the DCM unit time interval (t) evenly orsubstantially evenly (e.g., according to the nearest integer ornon-integer value).

Exemplary embodiments may be configured to automatically handle bothsynchronous and asynchronous time domains. When the DCM and the MPU havesynchronous time domains, the nominal command references may bedistributed evenly according to the nearest integer value. When the DCMand the MPU have asynchronous time domains, the nominal commandreferences may be distributed substantially evenly according to thenearest integer value.

Distributed control modules may be configured according to the presentdisclosure so as to allow for “plug and play” installation of thedistributed control module into a distributed control system. Thisincludes distributed control modules configured to self-configure forproviding cumulating command references and corresponding cumulatingcontrol commands. Exemplary distributed control modules may beconfigured to compatibly provide cumulating command references andcorresponding cumulating control commands using nominal commandreferences provided at any MPU unit time interval (u). This includesdistributed control system configurations in which a DCM unit timeinterval (t) and an MPU unit time interval (u) have synchronous timedomains, as well as configurations in which a DCM unit time interval (t)and an MPU unit time interval (u) have asynchronous time domains.

It is understood that terms “upstream” and “downstream” refer to therelative direction with respect to fluid flow in a fluid pathway. Forexample, “upstream” refers to the direction from which the fluid flows,and “downstream” refers to the direction to which the fluid flows. It isalso understood that terms such as “top”, “bottom”, “outward”, “inward”,and the like are words of convenience and are not to be construed aslimiting terms. As used herein, the terms “first”, “second”, and “third”may be used interchangeably to distinguish one component from anotherand are not intended to signify location or importance of the individualcomponents. The terms “a” and “an” do not denote a limitation ofquantity, but rather denote the presence of at least one of thereferenced item.

Here and throughout the specification and claims, range limitations arecombined and interchanged, and such ranges are identified and includeall the sub-ranges contained therein unless context or languageindicates otherwise. For example, all ranges disclosed herein areinclusive of the endpoints, and the endpoints are independentlycombinable with each other.

Approximating language, as used herein throughout the specification andclaims, is applied to modify any quantitative representation that couldpermissibly vary without resulting in a change in the basic function towhich it is related. Accordingly, a value modified by a term or terms,such as “about”, “approximately”, and “substantially”, are not to belimited to the precise value specified. In at least some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value, or the precision of the methods or machines forconstructing or manufacturing the components and/or systems.

Exemplary embodiments of the present disclosure will now be described infurther detail. FIG. 1 shows an exemplary distributed control system100. The distributed control system 100 may include a control system fora turbomachine or any other engine, machine, process, or plant, and mayinclude a large number of distributed control modules distributedthroughout the distributed control system 100. By way of example, adistributed control system 100 may include or be incorporated into afull authority direct engine control (FADEC) system or an engine controlunit (ECU) for a turbomachine and/or an aircraft.

As shown, an exemplary distributed control system 100 may include a mainprocessing unit 102, one or more distributed control modules 104, andone or more controllable components 112 respectively associated withcorresponding distributed control modules 104. The distributed controlsystem 100 distributes control processing among the distributed controlmodules 104. Typically, the main processing unit 102 providescentralized, supervisory control for the distributed control modules104, and the respective distributed control modules 104 implement one ormore control loops for controlling one or more controllable components112 associated with the corresponding distributed control module 104according to the supervisory control from the main processing unit 102.A main processing unit 102 may include a data warehouse and a serverconfigured to transmit data from the data warehouse to distributedcontrol modules 104 and/or to receive data from the distributed controlmodules 104 and to store the received data in the data warehouse forfurther purposes.

Operations and methods associated with a distributed control system 100,including operations and methods associated with a distributed controlmodule 104, may be implemented within the context of a turbomachine 800(FIG. 8 ), such as a turbomachine 800 installed on an aircraft. Theoperations and methods described herein may be carried out, for example,during flight, as well as during pre-flight and/or post-flightprocedures.

Any number of distributed control modules 104 may be provided. By way ofexample, the exemplary distributed control system 100 shown in FIG. 1includes a first distributed control module 106, a second distributedcontrol module 108, and an Nth distributed control module 110. Adistributed control module 104 may be associated with one or morecontrollable components 112. By way of example, the exemplarydistributed control system 100 shown in FIG. 1 includes a firstcontrollable component 114 associated with the first distributed controlmodule 106, a second controllable component 116 associated with thesecond distributed control module 108, and an Nth controllable component118 associated with the Nth distributed control module 110. However, itwill be appreciated that a plurality of controllable components 112 maybe associated with an individual distributed control module 104, and/orthat an individual controllable component 112 may be associated with aplurality of distributed control modules 104.

By way of example, a controllable component 112 may include an actuatoror a servo-actuator, and a sensor may include a position sensorconfigured to measure a position of the actuator or servo-actuator. Asanother example, a controllable component 112 may include avariable-geometry component, or an actuator or servo-actuator coupled toa variable-geometry component. Exemplary variable-geometry componentsinclude fuel valves, variable-position fan blades, variable-positionguide vanes, variable-position compressor blades, and variable-positionturbine blades.

An exemplary distributed control module 104 is shown in FIG. 2 . Asshown, a distributed control module 104 may include one or morecontrollers 200 communicatively coupled to a main processing unit 102and one or more controllable components 112. The controller may beconfigured to control the one or more controllable components 112 byimplementing a control loop or combination of control loops undersupervisory control from the main processing unit 102. Exemplary controlloops that may be implemented by the controller 200 include open-loopcontrol, closed-loop control, as well as a combination thereof.

As used herein, the terms “open-loop” or “open-loop control” generallyrefer to a control loop or control command that does not receivefeedback from a measured output variable of a system subject to suchcontrol loop or control command.

As used herein, the terms “closed-loop” or “closed-loop control”generally refer to a control loop or control command that utilizes as aninput or depends on feedback from, a measured output variable of asystem subject to such control loop or control command. Such a measuredoutput variable may include a measurement from a sensor configured tomeasure a system variable that depends on an input by such control loopor control command. A controller 200 that utilizes closed-loop controlmay compare a measured output variable to a setpoint to determine anerror value, which may be used, for example, in a PID control model orany other desired control model.

An exemplary distributed control module 104 may include a communicationinterface 204 configured to communicatively couple the distributedcontrol module 104 and the main processing unit 102 via wired orwireless communication lines 205. The communication lines 205 mayinclude a data bus or a combination of wired and/or wirelesscommunication links. The communication interface 204 may include anysuitable components for interfacing with one or more network(s),including for example, data busses, transmitters, receivers, ports,controllers, antennas, and/or other suitable components. An exemplarydistributed control module 104 may additionally include a power supplyinterface 206 operably coupled to a power supply unit 208, and a sensorinterface 210 operably coupled to one or more sensors 212.

Now turning to FIG. 3 , an exemplary controller 200 of a distributedcontrol module 104 will be described. As shown, an exemplary controller200 may include a control command module 300, a command referencegeneration module 302, and a control logic module 304. The commandreference generation module 302 and/or the control logic module 304 maybe included as part of the control command module or as separate modulesof the controller 200.

The control command module 300 may also include one or more controlmodes, including one or more closed loop control modes, one or more openloop control modes, and/or a disconnect control mode. The controlcommand module 300 may be configured to output control commands to oneor more controllable components. The control commands may be based atleast in part on a series of cumulating command references as describedherein.

The command reference generation module 302 may be configured togenerate and/or select a command reference for use in control logic of acontrol loop handled by the controller 200 or the distributed controlmodule 104. The command reference generation module 302 may generate aseries of cumulating command references as described herein.Additionally, or in the alternative, the command reference generationmodule 302 may be configured to select from among a number of possiblecommand references for use in the control loop, or to cause anothermodule associated with the controller 200 to utilize one of a number ofpossible command references in the control loop.

The control logic module 304 may be configured to process control logicassociated with one or more control loops handled by the controller 200or the distributed control module 104, including control logic for oneor more closed-loop and/or open-loop control regimes. The control logicmay include machine-executable instructions that can be executed by oneor more processors associated with the controller 200 or the distributedcontrol module 104.

The controller 200 may include one or more computing devices, includingone or more processors 306 and one or more memory devices 308, and suchcomputing devices are preferably located locally to the distributedcontrol module 104. The one or more processors 306 may include anysuitable processing device, such as a microprocessor, microcontroller,integrated circuit, logic device, and/or other suitable processingdevice. The one or more memory devices 308 may include one or morecomputer-readable media, including but not limited to non-transitorycomputer-readable media, RAM, ROM, hard drives, flash drives, and/orother memory devices 308.

The one or more memory devices 308 may store information accessible bythe one or more processors 306, including machine-executableinstructions 310 that can be executed by the one or more processors 306.The instructions 310 may include any set of instructions 310 which whenexecuted by the one or more processors 306 cause the one or moreprocessors 306 to perform operations. In some embodiments, theinstructions 310 may be configured to cause the one or more processors306 to perform operations, including operations for which the controller200, the distributed control module 104, and/or the one or morecomputing devices are configured. More particularly, such operations mayinclude operations of the command reference generation module 302,operations of the control logic module 304, and/or operations of thecontrol command module 300. Operations of the command referencegeneration module 302 may include generating a series of cumulatingcommand references as described herein.

Processor 306 operations may additionally include controlling the one ormore controllable components 112 according to a control loop, forexample, using a series of cumulating command references 406. Suchoperations may additionally or alternatively include receiving inputsfrom the one or more sensors 212 and controlling the one or morecontrollable components 112 responsive to the one or more sensors 212according to a control loop. Such operations may additionally oralternatively be carried out according to supervisory control providedby the main processing unit 102. The machine-executable instructions 310can be software written in any suitable programming language or can beimplemented in hardware. Additionally, and/or alternatively, theinstructions 310 can be executed in logically and/or virtually separatethreads on processors 306.

The memory devices 308 may store data 312 accessible by the one or moreprocessors 306. The data 312 can include current or real-time data, pastdata, or a combination thereof. The data 312 may be stored in a datalibrary 314. As examples, the data 312 may include data 312 associatedwith or generated by the main processing unit 102, the one or moresensors 212, and/or the distributed control module 104, including data312 associated with or generated by a controller 200 or a processor 306.The data 312 may also include other data sets, parameters, outputs,information, associated with the distributed control module 104 or thedistributed control system 100.

The communication interface 204 may additionally or alternatively allowthe distributed control module 104 and/or the main processing unit 102to communicate with a user interface 316.

Now referring to FIGS. 4A and 4B, and exemplary command referencegeneration module 302 will be described. As shown in FIG. 4A, anexemplary command reference generation module 302 may include a delayline module 400 and an accumulator module 402. The command referencegeneration module 302 may be configured to receive a nominal commandreference 404 and to determine a series of cumulating command references406 based at least in part on the nominal command reference 404. Theseries of cumulating command references 406 may be determined at leastin part using the delay line module 400 and/or the accumulator module402.

The main processing unit 102 may operate according to an MPU unit timeinterval (u), with (u) representing a unit of time of an MPU clock. Thedistributed control module 104 may operate according to a DCM unit timeinterval (t), with (t) representing a unit of time of a DMC clock. Thecommand reference generation module 302 may automatically generatecumulating command references 406 regardless of whether the DCM unittime interval (t) and the MPU unit time interval (u) may havesynchronous or asynchronous time domains. The MPU unit time interval (u)may exceed the DCM unit time interval (t). Generally, the commandreference generation module 302 may be configured to augment the nominalcommand reference 404 from the main processing unit 102 based at leastin part on a difference between the unit of time of the DMC clock (t),and the unit of time of the MPU clock, (u). For example, in exemplaryembodiments the unit of time of the DMC clock (t) may have a shorterduration than the unit of time of the MPU clock (u), such that thedistributed control module 104 may be capable of operating faster thanthe main processing unit 102. In one scenario, a distributed controlmodule may be capable of determining and/or outputting commandreferences and/or control commands to a controllable component 112 at arate that exceeds the rate at which nominal command references 404 areprovided by the main processing unit 102. In this scenario, the commandreference generation module 302 may be configured to upsample, expand,or interpolate the nominal command reference 404 so as to provide morefrequent command references and/or more frequent control commands, suchas the cumulating command references 406 and/or the cumulating controlcommands described herein.

As shown in FIGS. 4A and 4B, the command reference generation module 302may include a delay line module 400 configured to provide incrementalcommand references 408, and an accumulator module 402 configured toprovide cumulating command references. The incremental commandreferences 408 may be incremented by a command reference reciprocal (K)410, in which (K) represents a real number. In exemplary embodiments, acommand reference reciprocal (K) 410 may be an integer; however, inother embodiments a command reference reciprocal (K) 410 may also be anon-integer factor. The command reference reciprocal (K) 410 may beinput or selected by a user, such as via a user interface 204.Additionally, or in the alternative, the command reference reciprocal(K) 410 may be determined or selected by a distributed control module104 without requiring a user input. The nominal command reference 404may include an MPU command reference from a main processing unit dividedby the command reference reciprocal (K) 410.

In exemplary embodiments, the command reference reciprocal (K) 410 maybe input, determined, or selected such that a product of a DCM unit timeinterval (t) and the command reference reciprocal (K) 410 may beproportional to an MPU unit time interval (u) to within one unit of theDCM unit time interval (t). In some embodiments, the DCM unit timeinterval (t) and the MPU unit time interval (u) may have synchronoustime domains, for example, such that (K)-increments of the DCM unit timeinterval (t) equals one increment of the MPU unit time interval (u).Alternatively, in other embodiments the DCM unit time interval (t) andthe MPU unit time interval (u) may have asynchronous time domains.However, regardless of whether such time domains are synchronous orasynchronous, in exemplary embodiments, the command reference reciprocal(K) 410 may be input, determined, or selected such that a product of theDCM unit time interval (t) and the command reference reciprocal (K) 410is proportional to the MPU unit time interval (u) to within one unit ofthe DCM unit time interval (t).

In some embodiments, a command reference reciprocal (K) 410 may beinput, determined, or selected such that (K)-increments of the DCM unittime interval (t) may fall within one increment of the MPU unit timeinterval (u) by less than one increment of the DCM unit time interval(t). For example, a command reference reciprocal (K) 410 may be input,determined, or selected such that (K)-increments of the DCM unit timeinterval (t) exceeds one increment of the MPU unit time interval (u) byless than one increment of the DCM unit time interval (t), or such thatone increment of the MPU unit time interval (u) exceeds (K)-incrementsof the DCM unit time interval (t) by less than one increment of the DCMunit time interval (t). Alternatively, in some embodiments the commandreference reciprocal (K) 410 may be input, determined, or selected suchthat (K)-increments of the DCM unit time interval (t) equals oneincrement of the MPU unit time interval (u).

The delay line module 400 may include one or more delay lines 412, and adelay line 412 may be selected or configured based at least in part onthe command reference reciprocal (K) 410. For example, as discussed withreference to FIG. 4B, a delay line 412 may include a series of (K)-unitdelay operators 420. A delay line 412 having a desired number of unitdelay operators 420 may be determined, selected, generated, orconfigured by a distributed control module 104 and/or input or selectedby a user. For example, as shown in FIG. 4A, a delay line module 400 mayinclude a plurality of delay lines 412 from which a distributed controlmodule 104 and/or a user may select, such as a first delay line 414, asecond delay line 416, and an Nth delay line 418.

The distributed control module 104 and/or the delay line module 400 maydetermine or select a delay line 412 from among a plurality of delaylines 412, for example, based at least in part on a command referencereciprocal (K) 410. For example, a delay line 412 may be determined orselected that includes a series of (K)-unit delay operators 420. By wayof example, the first delay line 414 may include two delay lines 412.The first delay line 414 may be determined or selected when the commandreference reciprocal (K) 410 is 2. The second delay line 416 may includethree delay lines 412. The second delay line 416 may be determined orselected when the command reference reciprocal (K) 410 is 3. The Nthdelay line 418 may include N delay lines 412, and the Nth delay line 418may be determined or selected when the command reference reciprocal (K)410 is N.

In some embodiments, when the command reference reciprocal (K) 410 is anon-integer, the delay line 412 that has a number of unit delayoperators 420 that most closely approximates the non-integer value ofthe command reference reciprocal (K) 410 may be determined or selected.For example, the first delay line 414 having two delay lines 412 may beselected when the command reference reciprocal (K) 410 is a non-integerof between 1.1 and 2.5. As another example, the second delay line 416having three delay lines 412 may be selected when the command referencereciprocal (K) 410 is a non-integer of between 2.5 and 3.5. Further, thethird delay line 418 having N delay lines 412 may be selected when thecommand reference reciprocal (K) 410 is a non-integer of between (N−0.5)and (N+0.5).

Alternatively, a distributed control module 104 and/or the delay linemodule 400 may generate or configure a delay line 412 so as to provide aseries of (K)-unit delay operators 420. For example, a distributedcontrol module 104 may determine an MPU unit time interval (u) and a DCMunit time interval (t), and then the distributed control module 104 maydetermine a command reference reciprocal (K). The distributed controlmodule 104 may then generate or configure a delay line 412 having aseries of (K)-unit delay operators 420.

Now turning to FIG. 4B, an exemplary delay line module 400 and exemplaryoperations thereof will be further described. An exemplary delay line412 may include (K)-unit delay operators 420. By way of example, thecommand reference reciprocal (K) 410 may be three (3), and as shown, acorresponding delay line 412 may include three (3) unit delay operators420. Each of the unit delay operators 420 may be configured to delay thenominal command reference 404 input thereto by one DCM unit timeinterval (t), such as by perform a z-transform. The delay line module400 may determine a series of K(t)-incremental command references 408sequentially corresponding to one of (K)-increments of the DCM unit timeinterval (t), in which K(t) represents (K) increments as a function of(t). The series of K(t)-incremental command references 408 may bedetermined by the delay line module 400 at least in part using the delayline 412 and the command reference reciprocal (K) 410.

The delay line 412 may be configured to delay the nominal commandreference 404 using the series of (K)-unit delay operators 420 so as toprovide a series of K(t)-delayed nominal command references 404. TheK(t)-delayed nominal command reference 404 may be sequentially delayedby one of the (K)-increments of the DCM unit time interval (t). Forexample, a first unit delay operator 422 may receive the nominal commandreference 404 at an initial DCM unit time (t+0) and delay the nominalcommand reference 404 by a first increment of the DCM unit time interval(t). The first unit delay operator 422 may provide the nominal commandreference 404, as delayed (t+1), to a second unit delay operator 424 atthe first increment of the DCM unit time interval (t). The second unitdelay operator 424, having received the nominal command reference 404,as delayed (t+1), may further delay the nominal command reference 404 bya second increment of the DCM unit time interval (t+2). The second unitdelay operator 424 may provide the nominal command reference 404, asdelayed (t+2), to a third unit delay operator 426 at the secondincrement of the DCM unit time interval (t+2). The third unit delayoperator 426, having received the nominal command reference 404, asdelayed (t+2), may further delay the nominal command reference 404 by athird increment of the DCM unit time interval (t+3). The third unitdelay operator 426 may provide the nominal command reference 404, asdelayed (t+3), to a subtraction operator 428 at the third increment ofthe DCM unit time interval (t+3).

Meanwhile, the first unit delay operator 422 may sequentially receivesubsequent nominal command references 404 at sequentially subsequentincrements of the DCM unit time interval (t), with such sequentiallysubsequent nominal command references 404 passing through the series ofunit delay operators 420 at sequential DCM unit time intervals (t) tothe subtraction operator 428. The nominal command reference 404 may beupdated by the main processing unit 102 at MPU unit time intervals (u).

The subtraction operator 428 may be configured to sequentially subtractrespective ones of the series of K(t)-delayed nominal command references404 from the nominal command reference 404 corresponding to respectiveones of the (K)-increments of the DCM unit time interval (t), providinga series of K(t)-reference differences 430 sequentially corresponding toone of the (K)-increments of the DCM unit time interval (t). Forexample, at an initial DCM unit time (t+0), the subtraction operator 428may subtract an initial condition from the nominal command reference404. At the initial DCM unit time (t+0), the series of (K)-unit delayoperators 420 would have not yet provided the nominal command reference404 to the subtraction operator 428, because the series of (K)-unitdelay operators 420 would delay the nominal command reference 404 by the(K)-increments of the DCM unit time interval (t).

To illustrate, if a nominal command reference 404 has a value of 5 andan initial condition has a value of zero (0), the subtraction operator428 may subtract zero (0) from 5 at an initial DCM unit time (t+0). At(K)-increments of the DCM unit time interval (t+K), the series of(K)-unit delay operators 420 may provide the nominal command reference404, as delayed (t+K), to the subtraction operator 428, and thesubtraction operator 428 may subtract the nominal command reference 404at (t+K) from the nominal command reference 404 as delayed (t+K). Forexample, if the nominal command reference 404 still has a value of 5 ata DCM unit time (t+K), the subtraction operator 428 may subtract 5 from5 at the DCM unit time (t+K). As another example, if the nominal commandreference 404 has a value of 10 at a DCM unit time (t+K), thesubtraction operator 428 may subtract 5 from 10 at the DCM unit time(t+K).

Still referring to FIG. 4B, the subtraction operator 428 may provide aseries of K(t)-reference differences 430. A multiplier 432 may beconfigured to sequentially multiply respective ones of the series ofK(t)-reference differences 430 by the command reference reciprocal (K)410 corresponding to respective ones of the (K)-increments of the DCMunit time interval (t). Such sequential multiplying by the multiplier432 may provide a series of K(t)-incremental command references 408sequentially corresponding to one of the (K)-increments of the DCM unittime interval (t).

Referring again to FIG. 4A, the accumulator module 402 may receive theseries of K(t)-incremental command references 408 and determine a seriesof K(t)-cumulating command references 406 sequentially corresponding toone of the (K)-increments of the DCM unit time interval (t). The seriesof K(t)-cumulating command reference 406 may be determined based atleast in part on the series of K(t)-incremental command references 408.The accumulator module 402 may be configured to accumulate the series ofK(t)-incremental command references 408 sequentially corresponding toone of the (K)-increments of the DCM unit time interval (t). Forexample, the accumulator module 402 may add or sum (a) aK(t+0)-incremental command reference 408 corresponding to a K(t+0)-DCMunit time interval (t+0) and (b) a K(t−1)-incremental command reference408 corresponding to a K(t−1)-DCM unit time interval (t).

In an exemplary embodiment, as shown in FIG. 4A, an accumulator module402 may include a resampler 434 and an addition operator 436. Theresampler 434 may be configured to sequentially resample the series ofK(t)-cumulating command references 406 and sequentially delay theK(t)-cumulating command references 406 by an increment of the DCM unittime interval (t). For example, the resampler 434 may be configured toresample the K(t+0)-cumulating command reference 406 corresponding tothe K(t+0)-DCM unit time interval (t+0), and to delay theK(t+0)-cumulating command reference 406 by the DCM unit time interval(t). The resampler 434 may provide to the addition operator 436, the(t+0)-cumulating command reference 406, as delayed (t+1). Meanwhile thedelay line module 400 may provide to the addition operator 436, aK(t+1)-incremental command reference 408 corresponding to a K(t+1)-DCMunit time interval (t). The addition operator 436 may add or sum (a) theK(t+1)-incremental command reference 408 corresponding to the K(t+1)-DCMunit time interval (t) and (b) the K(t+0)-cumulating command referenceafter having been delayed, at the resampler 434, by the DCM unit timeinterval (t).

Now referring to FIGS. 5A-5C, graphically depicted are exemplary nominalcommand references 404 input to a command reference generation module302 and corresponding cumulating command references 406 output by thecommand reference generation module 302. FIG. 5A corresponds to adistributed control module 104 that has a DCM clock providing a DCM unittime interval (t) that is synchronous with an MPU clock providing an MPUunit time interval (u), such that the DCM unit time interval (t) and theMPU unit time interval (u) may have synchronous time domains. As shown,the MPU unit time interval (u) is three times longer than the DCM unittime interval (t). In the example depicted in FIG. 5A, the commandreference reciprocal (K) 410 has been accordingly set to 3. As a result,the command reference generation module 302 provides a series ofK(t)-cumulating command references 406 that cumulate over threeintervals of the DCM unit time interval (t), matching the nominalcommand reference 404 at intervals of the MPU unit time interval (u).

FIGS. 5B and 5C correspond to a distributed control module 104 that hasa DCM clock providing a DCM unit time interval (t) that is asynchronouswith an MPU clock providing an MPU unit time interval (u), such that theDCM unit time interval (t) and the MPU unit time interval (u) may haveasynchronous time domains. In the scenarios depicted in FIGS. 5B and 5C,the MPU unit time interval (u) is approximately three times longer thanthe DCM unit time interval (t), and the command reference reciprocal (K)410 has been set to 3. As shown in FIG. 5B, the MPU unit time interval(u) is slightly greater than three times the DCM unit time interval (t).As shown in FIG. 5C, the MPU unit time interval (u) is slightly lessthan three times the DCM unit time interval (t). In both of thesescenarios, the next K(t)-cumulating command reference 406 following aninterval of the MPU unit time interval (u) may be delayed by a fractionof the DCM unit time interval (t). Such delay may be accepted and stillrealize advantages of the present disclosure, for example, because thedelay is less than an interval of the MPU unit time interval (u).Alternatively, the command reference reciprocal (K) 410 may be set to anon-integer value, which may eliminate such asynchronous time domain.

Now referring to FIG. 6 , an exemplary control logic module 304 will bedescribed. As shown in FIG. 6 , an exemplary control logic module 304may include a plurality of control regimes which may be selected. By wayof example, a control logic module 304 may include one or morevariations of closed-loop control logic 600 and/or one or morevariations of open-loop control logic 602. The control logic module 304may select from among one or more variations of closed-loop or open-loopcontrol logic 600, 602, based on any desired criterion. For example,control logic 600, 602 may be selected based on an input from the mainprocessing unit 102 and/or based at least in part on an input from oneor more sensors 212. The control logic module 304 may be configured toreceive a series of cumulating command references 406, such as from thecommand reference generation module 302. Using selected control logic600, 602, the control logic module 304 may be configured to determine aseries of cumulating control commands 604. The series of cumulatingcontrol commands 604 may be determined based at least in part on theseries of cumulating command references 406. The control logic module304 and/or the control command module 300 may further be configured tooutput the series of cumulating control commands 604 to a controllablecomponent 112.

Now turning to FIGS. 7A-7E, exemplary methods 700 of controlling acontrollable component 112 will be discussed. As shown in FIG. 7A, anexemplary method 700 may include, at block 702, receiving a nominalcommand reference 404 from a main processing unit 102; at block 704,determining a series of cumulating command references 406 based at leastin part on the nominal command reference 404; and at block 706,determining a series of cumulating control commands 604 for acontrollable component 112. The series of cumulating control commands604 may be based at least in part on the series of cumulating commandreferences 406. An exemplary method 700 may additionally include, atblock 708, outputting the series of cumulating control commands 604 to acontrollable component 112.

FIG. 7B shows exemplary aspects of determining a series of cumulatingcommand references 406 based at least in part on the nominal commandreference 404, at block 704. As shown, in an exemplary method 700, block704 may include, at block 710, determining a command referencereciprocal (K) 410. In exemplary embodiments, (K) may represent a realnumber, including an integer or a non-integer value. An exemplary method700 may additionally include, at block 712, determining a series ofK(t)-incremental command references 408 sequentially corresponding toone of (K)-increments of a DCM unit time interval (t), in which (t)represents a unit of time of a DMC clock, and K(t) represents (K)increments as a function of (t). Further, an exemplary method mayinclude, at block 714, determining a series of K(t)-cumulating commandreferences 406 sequentially corresponding to one of the (K)-incrementsof the DCM unit time interval (t). The series of K(t)-cumulating commandreference 406 may be determined based at least in part on the series ofK(t)-incremental command references 408.

FIG. 7C shows exemplary aspects of determining a series ofK(t)-incremental command references 408 sequentially corresponding toone of (K)-increments of a DCM unit time interval (t), at block 712. Asshown, in an exemplary method 700, block 712 may include, at block 716,delaying the nominal command reference 404 by a delay line 412. Thedelay line 412 may include a series of (K)-unit delay operators 420. Theseries of (K)-unit delay operators 420 may be configured to provide aseries of K(t)-delayed nominal command references 404, with theK(t)-delayed nominal command reference 404 sequentially delayed by oneof the (K)-increments of the DCM unit time interval (t). An exemplarymethod 700 may additionally include, at block 718, sequentiallysubtracting respective ones of the series of K(t)-delayed nominalcommand references 404 from the nominal command reference 404corresponding to respective ones of the (K)-increments of the DCM unittime interval (t), providing a series of K(t)-reference differences 430sequentially corresponding to one of the (K)-increments of the DCM unittime interval (t). At block 720, an exemplary method 700 may includesequentially multiplying respective ones of the series of K(t)-referencedifferences 430 by the command reference reciprocal (K) 410corresponding to respective ones of the (K)-increments of the DCM unittime interval (t), providing the series of K(t)-incremental commandreferences 408 sequentially corresponding to one of the (K)-incrementsof the DCM unit time interval (t).

FIG. 7D shows an exemplary embodiment of determining a series ofK(t)-cumulating command references 406 sequentially corresponding to oneof the (K)-increments of the DCM unit time interval (t), at block 714.As shown, in an exemplary method 700, block 714 may include, at block722, accumulating the series of K(t)-incremental command references 408sequentially corresponding to one of the (K)-increments of the DCM unittime interval (t). The accumulating may include summing aK(t+0)-incremental command reference 408 corresponding to a K(t+0)-DCMunit time interval (t+0) and a K(t−1)-incremental command reference 408corresponding to a K(t−1)-DCM unit time interval (t).

FIG. 7E shows another exemplary embodiment of determining a series ofK(t)-cumulating command references 406 sequentially corresponding to oneof the (K)-increments of the DCM unit time interval (t), at block 714.As shown in FIG. 7E, and exemplary method 700 may include, at block 724,determining a K(t+0)-cumulating command reference 406 corresponding to aK(t+0)-DCM unit time interval (t+0). The K(t+0)-cumulating commandreference 406 may include the K(t+0)-incremental command reference 408corresponding to the K(t+0)-DCM unit time interval (t+0). An exemplarymethod may further include, at block 726, resampling theK(t+0)-cumulating command reference 406 corresponding to the K(t+0)-DCMunit time interval (t+0), and at block 728, delaying theK(t+0)-cumulating command reference 406 by the DCM unit time interval(t). At block 730, an exemplary method 700 may include determining aK(t+1)-cumulating command reference 406 corresponding to a K(t+1)-DCMunit time interval (t). The K(t+1)-cumulating command reference 406 mayinclude the sum of (a) a K(t+1)-incremental command reference 408corresponding to a K(t+1)-DCM unit time interval (t) and (b) theK(t+0)-cumulating command reference 406 after having been delayed by theDCM unit time interval (t).

It will be appreciated that while the exemplary embodiments aregenerally depicted as a linear system, it will be appreciated that thescope of the present disclosure also embraces non-linear, higher-order,and otherwise more complex system. For example, it will be appreciatedthat the z-transforms depicted with respect to the command referencegeneration module 302 (e.g., the z-transforms for the unit delays in thedelay line module 400 and/or for resampling in the accumulator module402) may be implemented using other methods of Fourier transform, all ofwhich are within the scope of the present disclosure. As anotherexample, it will be appreciated that operations of the command referencegeneration module 302 may be implemented using other signal processingtechniques, including, without limitation, recursive filters such asinfinite impulse response filters or finite impulse response filters.

Aspects of the presently disclosure may be incorporated into, orotherwise utilized with, any process, system, or machine where adistributed control system 100 and/or distributed control module 104 maybe desirable. By way of example, the present disclosure may beimplemented with a turbomachine, such as a turbofan engine 800. FIG. 8provides a schematic, cross-sectional view of a turbofan engine 800 inaccordance with an exemplary embodiment of the present disclosure. Theengine 800 may be incorporated into a vehicle, such as an aircraft, amarine vessel, or a land vehicle. For example, the engine 800 may be anaeronautical engine incorporated into an aircraft. Alternatively,however, the engine may be any other suitable type of engine for anyother suitable vehicle.

For the embodiment depicted, the engine is configured as a high bypassturbofan engine 800. As shown in FIG. 8 , the turbofan engine 800defines an axial direction A (extending parallel to a longitudinalcenterline 801 provided for reference), a radial direction R, and acircumferential direction (extending about the axial direction A; notdepicted in FIG. 8 ). In general, the turbofan 800 includes a fansection 802 and a turbomachine 804 disposed downstream from the fansection 802.

The exemplary turbomachine 804 depicted generally includes asubstantially tubular outer casing 806 that defines an annular inlet808. The outer casing 806 encases, in serial flow relationship, acompressor section including a booster or low pressure (LP) compressor810 and a high pressure (HP) compressor 812; a combustion section 814; aturbine section including a high pressure (HP) turbine 816 and a lowpressure (LP) turbine 818; and a jet exhaust nozzle section 820. Thecompressor section, combustion section 814, and turbine section togetherdefine at least in part a core air flowpath 821 extending from theannular inlet 808 to the jet nozzle exhaust section 820. The turbofanengine further includes one or more drive shafts. More specifically, theturbofan engine includes a high pressure (HP) shaft or spool 822drivingly connecting the HP turbine 816 to the HP compressor 812, and alow pressure (LP) shaft or spool 824 drivingly connecting the LP turbine818 to the LP compressor 810.

For the embodiment depicted, the fan section 802 includes a fan 826having a plurality of fan blades 828 coupled to a disk 830 in a spacedapart manner. The fan blades 828 and disk 830 are together rotatableabout the longitudinal axis 801 by the LP shaft 824. The disk 830 iscovered by rotatable front hub 832 aerodynamically contoured to promotean airflow through the plurality of fan blades 828. Further, an annularfan casing or outer nacelle 834 is provided, circumferentiallysurrounding the fan 826 and/or at least a portion of the turbomachine804. The nacelle 834 is supported relative to the turbomachine 804 by aplurality of circumferentially-spaced outlet guide vanes 836. Adownstream section 838 of the nacelle 834 extends over an outer portionof the turbomachine 804 so as to define a bypass airflow passage 840therebetween.

Referring still to FIG. 8 , the turbofan engine 800 additionallyincludes a fuel delivery system 842. The fuel delivery system 842generally includes a fuel source 844, such as a fuel tank, and one ormore fuel lines 846. The one or more fuel lines 846 provide a fuel flowthrough the fuel delivery system 842 to the combustion section 814 ofthe turbomachine 804 of the turbofan engine 800. The fuel deliverysystem may include one or more controllable components 112, such as afuel valve or an actuator or servo-actuator coupled to a fuel valve. Oneor more sensors 212 may be operable coupled, respectively, to the one ormore controllable components 112. The one or more controllablecomponents 112 may be controlled using a distributed control module 104,which may be communicatively coupled to a distributed control system100. The one or more sensors 212 may be communicatively coupled to thedistributed control module 104, for example, so as to provide aclosed-loop control regime. Alternatively, the distributed controlmodule 104 may provide an open-loop control regime.

It will be appreciated that the exemplary turbofan engine 800 depictedin FIG. 8 is provided by way of example only. In other exemplaryembodiments, any other suitable engine may be utilized with aspects ofthe present disclosure. For example, in other embodiments, the enginemay be any other suitable gas turbine engine, such as a turboshaftengine, turboprop engine, turbojet engine, etc. In such a manner, itwill further be appreciated that in other embodiments the gas turbineengine may have any other suitable configuration, such as any othersuitable number or arrangement of shafts, compressors, turbines, fans,etc. Further, still, in alternative embodiments, aspects of the presentdisclosure may be incorporated into, or otherwise utilized with, anyother suitable type of gas turbine engine, such as an industrial gasturbine engine incorporated into a power generation system, a nauticalgas turbine engine, etc. any other type of engine, such as reciprocatingengines.

Further, although not depicted herein, in other embodiments an exemplaryengine 800 may include any number of distributed control modules 104configured to control various controllable components 112 of the engine800, including variable-geometry components include variable-positionfan blades, variable-position guide vanes, variable-position compressorblades, and variable-position turbine blades. Such distributed controlmodules 104 may be part of a single distributed control system 100 orpart of a plurality of distributed control systems 100.

An exemplary distributed control system 100 may include a mainprocessing unit 102, a distributed control module 104, and acontrollable component 112. The distributed control module 104 may beconfigured according to the present disclosure, for example, to receivea nominal command reference 404, such as from the main processing unit102; to determine a series of cumulating command references 406, forexample, based at least in part on the nominal command reference 404;and to determine a series of cumulating control commands 604 based atleast in part on the series of cumulating command references 406. Thedistributed control module 104 may additionally be configured to outputthe series of cumulating control commands 604 to a controllablecomponent 112.

In some embodiments, an exemplary distributed control system 100 mayadditionally include a sensor 212 configured to measure a systemvariable of the controllable component 112. For example, the sensor 212may include a position sensor configured to measure a position of anactuator or servo-actuator. The distributed control module 104 may beconfigured to receive sensor feedback from the sensor 212, and to usethe sensor feedback in a closed-loop control regime that includes theseries of cumulating control commands 604. Additionally, or in thealternative, the distributed control module 104 may be configured toprovide an open-loop control regime.

The distributed control system 100 may include any suitable controllablecomponents 112. An exemplary controllable component 112 may include anactuator or a servo-actuator, which may be coupled to avariable-geometry component. By way of example, a variable-geometrycomponent may include a fuel valve, a variable-position fan blade, avariable-position guide vane, a variable-position compressor blade, or avariable-position turbine blade.

Aspects of the present disclosure may also be implemented in computerreadable medium. Exemplary computer readable medium may includecomputer-executable instructions 310 configured according to the presentdisclosure. For example, computer-executable instructions 310, whenexecuted by one or more processors 306 of a distributed control module104, may cause the distributed control module 104 to: receive a nominalcommand reference 404 from a main processing unit 102; determine aseries of cumulating command references 406 based at least in part onthe nominal command reference 404; and determine a series of cumulatingcontrol commands 604 based at least in part on the series of cumulatingcommand references 406. Exemplary computer-executable instructions 310may additionally be configured to cause the distributed control module104 to output the series of cumulating control commands 604 to acontrollable component 112. Exemplary computer readable medium may beincorporated into or utilized with a FADEC system or an ECU, such as fora turbomachine or turbofan engine 800 and/or an aircraft.

This written description uses exemplary embodiments to describe thepresently disclosed subject matter, including the best mode, and also toenable any person skilled in the art to practice such subject matter,including making and using any devices or systems and performing anyincorporated methods. The patentable scope of the presently disclosedsubject matter is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method of controlling a controllable componentof a turbomachine, the method comprising: receiving a nominal commandreference from a main processing unit; determining a series ofcumulating command references based at least in part on the nominalcommand reference; and wherein determining the series of cumulatingcommand references comprises: determining a command reference reciprocal(K), wherein the command reference reciprocal (K) represents a realnumber; determining a series of K(t)-incremental command referencessequentially corresponding to one of (K)-increments of a DCM unit timeinterval (t), wherein the DCM unit time interval (t) represents a unitof time of a DMC clock, and wherein the series of K(t)-incrementalcommand references represents the (K)-increments as a function of theDCM unit time interval (t); and determining a series of K(t)-cumulatingcommand references sequentially corresponding to one of the(K)-increments of the DCM unit time interval (t), the series ofK(t)-cumulating command reference determined based at least in part onthe series of K(t)-incremental command references; outputting a seriesof cumulating control commands to the controllable component of theturbomachine, the series of cumulating control commands based at leastin part on the series of cumulating command references, the controllablecomponent including at least one of a variable-geometry component, anactuator operably coupled to the variable-geometry component, and aservo-actuator coupled to the variable-geometry component, whereinoutputting the series of cumulating control commands to the controllablecomponent of the turbomachine effects control of the controllablecomponent.
 2. The method of claim 1, wherein determining the series ofK(t)-incremental command references comprises: delaying the nominalcommand reference by a delay line, the delay line comprising a series of(K)-unit delay operators, the series of (K)-unit delay operatorsconfigured to provide a series of K(t)-delayed nominal commandreferences, the K(t)-delayed nominal command reference sequentiallydelayed by one of the (K)-increments of the DCM unit time interval (t);sequentially subtracting respective ones of the series of K(t)-delayednominal command references from the nominal command referencecorresponding to respective ones of the (K)-increments of the DCM unittime interval (t), providing a series of K(t)-reference differencessequentially corresponding to one of the (K)-increments of the DCM unittime interval (t); and sequentially multiplying respective ones of theseries of K(t)-reference differences by the command reference reciprocal(K) corresponding to respective ones of the (K)-increments of the DCMunit time interval (t), providing the series of K(t)-incremental commandreferences sequentially corresponding to one of the (K)-increments ofthe DCM unit time interval (t).
 3. The method of claim 1, whereindetermining the series of K(t)-cumulating command references comprises:accumulating the series of K(t)-incremental command referencessequentially corresponding to one of the (K)-increments of the DCM unittime interval (t), the accumulating comprising summing aK(t+0)-incremental command reference corresponding to a K(t+0)-DCM unittime interval (t+0) and a K(t−1)-incremental command referencecorresponding to a K(t−1)-DCM unit time interval (t).
 4. The method ofclaim 1, wherein determining the series of K(t)-cumulating commandreferences comprises: determining a K(t+0)-cumulating command referencecorresponding to a K(t+0)-DCM unit time interval (t+0), theK(t+0)-cumulating command reference comprising a K(t+0)-incrementalcommand reference corresponding to a K(t+0)-DCM unit time interval(t+0); and determining a K(t+1)-cumulating command referencecorresponding to a K(t+1)-DCM unit time interval (t), theK(t+1)-cumulating command reference comprising a sum of aK(t+1)-incremental command reference corresponding to the K(t+1)-DCMunit time interval (t) and the K(t+0)-cumulating command reference afterhaving been delayed by the DCM unit time interval (t).
 5. The method ofclaim 4, comprising: resampling the K(t+0)-cumulating command referencecorresponding to the K(t+0)-DCM unit time interval (t+0); and delayingthe K(t+0)-cumulating command reference by the DCM unit time interval(t).
 6. The method of claim 1, comprising determining the series ofcumulating control commands based at least in part on the series ofcumulating command references.
 7. The method of claim 1, wherein thenominal command reference comprises an MPU command reference from a mainprocessing unit divided by the command reference reciprocal (K).
 8. Themethod of claim 7, wherein the main processing unit transmits the MPUcommand reference according to an MPU unit time interval (u), whereinthe MPU unit time interval (u) represents a unit of time of an MPUclock, and wherein the MPU unit time interval (u) exceeds the DCM unittime interval (t).
 9. The method of claim 8, wherein the DCM unit timeinterval (t) and the MPU unit time interval (u) may have synchronous orasynchronous time domains.
 10. The method of claim 8, comprising:determining the command reference reciprocal (K) such that a product ofthe DCM unit time interval (t) and the command reference reciprocal (K)is proportional to the MPU unit time interval (u) to within one unit ofthe DCM unit time interval (t).
 11. The method of claim 10, wherein: the(K)-increments of the DCM unit time interval (t) exceeds one incrementof the MPU unit time interval (u) by less than one increment of the DCMunit time interval (t); or one increment of the MPU unit time interval(u) exceeds the (K)-increments of the DCM unit time interval (t) by lessthan one increment of the DCM unit time interval (t).
 12. The method ofclaim 1, comprising: receiving sensor feedback from a sensor configuredto measure a system variable of the controllable component; and usingthe sensor feedback in a closed-loop control regime comprising theseries of cumulating control commands.
 13. The method of claim 12,wherein the sensor comprises a position sensor configured to measure aposition of the actuator or the servo-actuator.
 14. The method of claim1, wherein the variable-geometry component comprises a fuel valve, avariable-position fan blade, a variable-position guide vane, avariable-position compressor blade, or a variable-position turbineblade.
 15. A distributed control system, comprising: a main processingunit, a distributed control module, and a controllable component of aturbomachine, the distributed control module including at least one of aprocessor, a memory, and an interface, the controllable componentincluding at least one of a variable-geometry component, an actuatoroperably coupled to the variable-geometry component, and aservo-actuator coupled to the variable-geometry component, thedistributed control module configured to: receive a nominal commandreference from the main processing unit; determine a series ofcumulating command references based at least in part on the nominalcommand reference; determine a series of cumulating control commandsbased at least in part on the series of cumulating command references;and output the series of cumulating control commands to the controllablecomponent; to effect control of the controllable component.
 16. Thedistributed control system of claim 15, comprising: a sensor configuredto measure a system variable of the controllable component, the sensorcomprises a position sensor configured to measure a position of anactuator or servo-actuator; wherein the distributed control module isconfigured to: receive sensor feedback from the sensor; and use thesensor feedback in a closed-loop control regime comprising the series ofcumulating control commands.
 17. The distributed control system of claim16, wherein the controllable component comprises the actuator or theservo-actuator coupled to a variable-geometry component, thevariable-geometry component comprising: a fuel valve, avariable-position fan blade, a variable-position guide vane, avariable-position compressor blade, or a variable-position turbineblade.
 18. A non-transitory computer readable medium comprisingcomputer-executable instructions, which, when executed by one or moreprocessors of a distributed control module, cause the distributedcontrol module to: receive a nominal command reference from a mainprocessing unit; determine a series of cumulating command referencesbased at least in part on the nominal command reference; determine aseries of cumulating control commands based at least in part on theseries of cumulating command references; and output the series ofcumulating control commands to a controllable component of aturbomachine, the controllable component including at least one of avariable-geometry component, an actuator operably coupled to thevariable-geometry component, and a servo-actuator coupled to thevariable-geometry component, wherein output of the series of cumulatingcontrol commands to the controllable component effects control of thecontrollable component.
 19. The non-transitory computer readable mediumof claim 18, wherein the non-transitory computer readable medium isincorporated into or utilized with a full authority direct enginecontrol (FADEC) system or an engine control unit (ECU) for aturbomachine and/or an aircraft.